The present invention relates to a container to hold batteries for a mobile vehicle, such as a hybrid electric vehicle. More specifically, the container is made of a sturdy steel construction ant coated both internally and externally with a substance with high electrical resistance elastomer such as a combination polyurethane and polyurea elastomer. The use of the high electrical resistance elastomer coating allows the use of a steel container with reduced electrical shorting dangers. Steel is a preferred base material for the container or box because it is effective in providing shield for electromagnetic interference (EMI) and radio frequency interference (RFI) that is associated with the high voltage electricity running through batteries in hybrid electric vehicles.